The Russos, who are brothers and hail from Cleveland, directed "Civil War."

The movie follows the eponymous Captain America, portrayed by Chris Evans, in his quest to protect childhood friend Bucky Barnes -- previously brainwashed into serving as a terrorist assassin -- from government hit squads.

His efforts bring him into direct conflict with Iron Man, portrayed by Robert Downey Jr. After their first confrontation, other superheroes are forced to pick sides.

"We really did a radical reinterpretation of Captain America in 'Winter Soldier,'" said Joe Russo, who wore an "Ohio Against the World" t-shirt during a question and answer session Saturday. "We were twice as aggressive in tone and execution on 'Civil War.'"

The movie hits theaters May 6.

The Russos also took a moment during the panel to correct a mistake they made earlier this year when describing the plot to the upcoming "Avengers: Infinity War," which they are on board to direct.

The movie features 68 distinct characters, not 67.

Either way, it's a nearly overwhelming number of characters, and the brothers discussed the challenges in working with such a large number of players.

"We have to tell a story and that story has to be built around the characters' emotional arcs," said Joe Russo. "And we can only have so many of those."

Rather than fleshing out each individual, the film will focus on a handful of characters, and many superheroes will play ancillary roles, he said.

The pair was careful not to divulge too much information about their upcoming projects, but said "Civil War" is a continuation of the story started "Winter Soldier."

Bucky -- Captain America's sidekick turned Russian agent, turned Hydra Agent, turned Captain America's sidekick again -- plays a significant role in the movie, he said, and the relationship between him and Captain America will be further fleshed out in "Civil War," he said.

Spider-Man, one of the most popular superheroes of all time, appears in "Civil War," but so far no screen shots of the wall-crawler have been released and the character has appeared in neither of the two trailers.

The Russos declined to answer questions about his role in the story or what he will look like.

In the comic book story upon which "Civil War" is based, Iron Man convinced Spider-man -- who is portrayed by Tom Holland -- to reveal his secret identity to the world. It was a pivotal moment in the comic book storyline, and it is conceivable that something similar takes place in the movie.